1. Field of the Invention
The present invention relates to a method and system for limiting a program utilization period in a computer.
2. Description of the Related Art
Many problems of unauthorized usage and unauthorized copies of application programs have arisen recently in the field of computers. For protection of programs, therefore, a method has been adopted which restricts the kinds of computers that can use the programs by use of information specific to hardware of computer systems.
However, such a method takes no account of a factor with respect to a period of time. Thus, a program once stored in a computer system can be used semipermanently. For example, for programs for demonstration, usage of such program is not limited for a given period of time, nor is the user prevented from using the programs after the elapse of the given period of time. Accordingly, practically sufficient protection of programs cannot be accomplished.
In view of the above, a data processing apparatus is desired which can implement practically sufficient protection of programs by restricting the use of programs by a period of time.